A research group led by Professor Tadahiro Komeda at Institute of Multidisciplinary Research for Advanced Materials, Tohoku University has clarified electrical conduction pathways through molecules by measuring molecular vibration. The vibration is induced by passing electric current through molecular films. The research has been conducted as part of Core Research for Evolutional Science and Technology by Japan Science and Technology Agency.

 Researches in molecular-scale electronics have currently been miniaturized, and studies using electric current through a few molecules as an information unit have often been conducted. In such studies, we make electrodes whose gaps are just about a molecular size, and measure electrical conductivity after a few molecules are connected to electrodes. It has been expected to characterize molecules by various properties including molecular structures, electronic states and modification sites. However, most of fundamental matters have not been understood. For instance, it has not been answered to a basic question such as if electric current passes only along molecular frames or not.

 In this study, self-organized alkanethiol film was used as a sample on whose surface straight-line molecules were aligned. We produced a new device by connecting one side of molecules and a large gold electrode, and connecting the other side and a micro electrode in a single atomic unit using probes of a tunnel microscope. The research group has successfully analyzed conduction pathways by precise measurement of electric current and calculation simulations. The results show that electric current hops from a molecule to a molecule through the pathways, not only along molecular frames. It is considered to be the first achievement to precisely verify conduction pathways as a basis for molecular-scale electronics.

 The research results will be published online in Ｐｈｙｓｉｃａｌ Ｒｅｖｉｅｗ Ｌｅｔｔｅｒｓ soon.

[Contact]
(About Research)
Professor Tadahiro Komeda
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
Address: 2-1-1 katahira Aoba-ku Sendai, Miyagi, 980-8577, Japan
Tel: +81-22-217-5368, Fax: +81-22-217-5371
E-mail: komeda@tagen.tohoku.ac.jp

(About JST Projects)
Mr. Katsumi Hirota
Department of Inclusive Research Administration, Innovation Headquarters, Japan Science and Technology Agency
Address: Sanban-cho building, 5 Sanban-cho Chiyoda-ku, Tokyo, 102-0075, Japan
Tel: +81-3-3512-3524, Fax: +81-3-3222-2064
E-mail: crest@jst.go.jp